It goes round in either direction (5)
I believe the answer is:
rotor
'it goes round' is the definition.
(I've seen this before)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for rotor that I've seen before include "Revolving part of a machine, a palindrome" , "Turning part of an engine" , "device for lifting a chopper" , "part of chopper" , "Revolving dynamic part" .)